Honestly, I'd rather see a continuation of XCX's story with a "remastered version" including several new chapters that extend the ambiguous plotholes. I thought Takahashi stated he wanted to make his next game different from a story and visual standpoint? I think both the original Xenoblade and its sequel have vastly different "moods" so I trust that the result will be something fabulous.
I understand your reasoning in regards to the unification of the platforms, but Project X Zone and XCX are games of completely different scope and likely resource management. Expecting two rather grand RPGs from Monolith in close succession is a risky proposition, as they are great engine builders, whose tech has been utilized by Nintendo in many games. They'll need to help out with creating some of the groundwork for Nintendo's efforts on NX before they can consider tackling even one of those games.